The invention relates to operating devices for manually actuating lifting devices.
For instance, a switch for manually actuating lifting devices is known from German application laid open DE 103 31 130 A1. The switch has a switch housing, in which several spring-loaded switching elements—such as for the lifting and lowering functions of a lifting device—are arranged. Each switching element includes of an electrical push button switch and a mechanical pressure switch for its actuation. The mechanical pressure switch is basically made up of a switch tappet and a sleeve. The switch tappet is guided in the sleeve for actuating the electrical push button switch, configured as a microswitch. The switch tappet is buttressed against the push button or a floor of the switch housing by a spring element in the form of a helical spring. The pressure switch can be one-step or multiple-step in configuration, starting from an off position, the switch tappet can be moved into a first on position and then to at least one additional on position. Accordingly, corresponding electrical push buttons or multiple-step push buttons are then actuated by the switch tappet in each of the on positions. In the off position, the switch tappet protrudes furthest out from the sleeve and it is then moved in the direction of the sleeve to reach the first or the additional on positions. In the last on position, the switch tappet still protrudes from the sleeve so that it can be felt by the user's thumb.
Furthermore, from the Spanish utility model ES 101 83 51 U there is known another switch for the manual actuating of lifting devices, which likewise has switching elements arranged in a switch housing with electrical push buttons and a mechanical pressure switch. The mechanical pressure switch also has a switch tappet and a sleeve, in which the switch tappet is guided for an activation of the electrical push button. Furthermore, the pressure switch here is also sealed off from the switch housing with a flexible covering element. Before the flexible covering element is mounted, the sleeve provided with an outer thread is screwed into an opening in the front surface of the switch housing until a sealing ring, bearing against a peripheral rim on the outside of the sleeve, comes to bear against the inside of the front surface of the switch housing. The covering element is then screwed from the outside onto the rest of the outer thread protruding from the front surface of the switch housing until the covering element comes to bear flush against the front surface of the switch housing. For this, the covering element has an inwardly directed peripheral groove in the region of its connection opening, in which is inserted a connection ring having an inner thread.
The protective caps of the switching elements are often subjected to special strain and often need to be replaced on account of wear.